Thursday, December 20, 2012

Cylinders Removed

It's almost Christmas and I won't have much time for a couple of weeks but I thought I'd have a look inside the engine.

First the heads and cylinders removed. You can see in the photo below that the pistons are in good condition and have been purposely scuffed with emery to hold oil.

 Looking at the photo of the top of the piston it's obvious that this piston has never been run. There is no colour on it at all.

The bores are in excellent condition.

I removed the other cylinder and it was in the same condition as this one. I'll split the crankcases after Christmas. I've never worked on an engine with vertically split cases before (excepting lawnmowers) but I guess it can't be too difficult. Gotta work out what's wrong with the gearbox.


  1. Great to see a TA125 being worked on. I had one back in the 80's and like a fool sold it for $200 back then. I'd really like to get another one as that's a bike I really regret letting go.
    My bike came with a certificate from Bonneville that said it ran 127mph if I remember correctly (icould very well be wrong). My pistons were definately cut down on the intake side. I know because I had a piston ring braeak which damaged the piston and when I replaced it I had to have it machined down. I thinkthe bike had been a bit "overtuned" as the power band was 1500rpm wide (11,000 to 12,5000 which made it difficult toride, especially with my inexperience at the time.

    1. Good to hear from, nice to know someone looks at this occasionally. I believe the 127mph, With the right gearing and a light rider with a long straight it's feasible. The power band would normally be about 2500rpm so yours was probably tuned up. You would get more power but as you say they become rather difficult to ride. $200 way too cheap even then but then again I sold my TZ250's way too cheap as well as a TZ750 engine. We live and learn.